vitamin b12 injection to oral conversion Efficacy of different routes of supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta-analysis Best Vitamin B12 Injection Site:

Additionally, pregnancy, prolonged use of antibiotics, anti-seizure medications, and some medications for type 2 diabetes, such as metformin, may impact vitamin B12 absorption

Vomiting blood: Often looks like coffee grounds and is a clear indicator of a GI emergency

Vitamin B12 also plays a vital role in maintaining the health of the nervous system by supporting the formation of myelinthe protective sheath around nerves that ensures fast, efficient signal transmission

First and foremost, they can help alleviate the symptoms associated with B12 deficiency, such as loss of appetite, weight loss, and gastrointestinal issues

2019;316:E34-E42

So, it could be that an ultrasound scan would be needed to try and diagnose that problem